Broadcast receiver and 3D subtitle data processing method thereof

ABSTRACT

A broadcast receiver and a 3D subtitle data processing method thereof are disclosed. A method for processing three dimensional (3D) subtitle data includes receiving, by a receiver, a broadcast signal including 3D subtitle data, extracting, by an extracting unit, subtitle display information for a base view and extended subtitle display information for an extended view from the 3D subtitle data, and controlling, by a controller, a 3D subtitle display using the subtitle display information for the base view and the extended subtitle display information for the extended view.

This application is a National Stage Entry of International ApplicationNo. PCT/KR2009/007109, filed on Dec. 1, 2009, and claims the benefit ofU.S. Provisional Application No. 61/152,234, filed Feb. 12, 2009, bothof which are hereby incorporated by reference for all purposes as iffully set forth herein in their entireties.

TECHNICAL FIELD

The present invention relates to a broadcast receiver and a threedimensional (3D) subtitle data processing method thereof, and moreparticularly to a broadcast receiver for receiving 3D subtitle data andprocessing the received 3D subtitle data in consideration of either adisplay condition of a 3D video display device or an effect intended bytransmission of subtitle data, and a method for processing the 3Dsubtitle data.

BACKGROUND ART

Generally, a three dimensional (3D) image (or a stereoscopic image)provides a user's eyes with a stereoscopic effect using the stereoscopicvisual principle. A human being feels both near and far through abinocular parallax caused by a distance between their eyes spaced apartfrom each other by about 65 mm, such that the 3D image enables bothright and left eyes to respectively view associated planar images,resulting in the stereoscopic effect and the perspective effect.

The above-mentioned 3D image display method may be classified into astereoscopic scheme, a volumetric scheme, a holographic scheme, etc. Incase of using the stereoscopic scheme, the 3D image display methodprovides a left view image to be viewed by the left eye and a right viewimage to be viewed by the right eye, such that the user's left eye viewsthe left view image and the user's right eye views the right view imagethrough either polarization glasses or a display device, resulting inrecognition of the 3D image effect.

DISCLOSURE OF INVENTION Technical Problem

Accordingly, the present invention is directed to a broadcast receiverand a 3D subtitle data processing method thereof that substantiallyobviate one or more problems due to limitations and disadvantages of therelated art.

An object of the present invention is to provide a broadcast receiverfor receiving 3D subtitle data under a 3D broadcast environment,processing the received 3D subtitle data in consideration of a displaycondition of a 3D video display device and a 3D effect intended by acontent manufacturer, displaying the processed 3D subtitle data, andthus providing a user with more effective and convenient broadcastenvironments, and 3D subtitle data processing method for use in thebroadcast receiver.

Solution to Problem

The object of the present invention can be achieved by providing amethod for processing three dimensional (3D) subtitle data, the methodincluding receiving, by a receiver, a broadcast signal including 3Dsubtitle data, extracting, by an extracting unit, subtitle displayinformation for a base view and extended subtitle display informationfor an extended view from the 3D subtitle data, and controlling, by acontroller, a 3D subtitle display using the subtitle display informationfor the base view and the extended subtitle display information for theextended view.

In another aspect of the present invention, provided herein is abroadcast receiver including a receiver for receiving a broadcast signalincluding 3D subtitle data, an extracting unit for extracting subtitledisplay information for a base view and extended subtitle displayinformation for an extended view from the 3D subtitle data, and acontroller for controlling a 3D subtitle display using the subtitledisplay information for the base view and the extended subtitle displayinformation for the extended view.

Advantageous Effects of Invention

According to embodiments of the present invention, the broadcastreceiver can process subtitle data according to a 3D effect of received3D subtitle data, and display the processed subtitle data.

In addition, according to embodiments of the present invention, a 3Dsubtitle data processing method maintains compatibility with a 2D legacybroadcast receiver, and at the same time displays subtitle data having a3D effect through a broadcast receiver capable of displaying 3D videodata.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention, illustrate embodiments of the inventionand together with the description serve to explain the principle of theinvention.

In the drawings:

FIG. 1 shows a syntax structure of an extended Display DefinitionSegment (DDS) acting as extended subtitle display information accordingto one embodiment of the present invention.

FIG. 2 shows a syntax structure of an extended Page Composition Segment(PCS) acting as extended subtitle display information according to oneembodiment of the present invention.

FIG. 3 shows a syntax structure of an extended Region CompositionSegment (RCS) acting as extended subtitle display information.

FIG. 4 shows a syntax structure of an extended Object Data Segment (ODS)acting as extended subtitle display information according to oneembodiment of the present invention.

FIG. 5 is a flowchart illustrating a method for receiving and processing3D subtitle data according to one embodiment of the present invention.

FIG. 6 is a block diagram illustrating a broadcast receiver forreceiving and processing 3D subtitle data according to one embodiment ofthe present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. The detailed description, which will be given below withreference to the accompanying drawings, is intended to explain exemplaryembodiments of the present invention, rather than to show the onlyembodiments that can be implemented according to the present invention.

Prior to describing the present invention, it should be noted that mostterms disclosed in the present invention are defined in consideration offunctions of the present invention and correspond to general terms wellknown in the art, and can be differently determined according tointention of those skilled in the art, usual practices, or introductionof new technologies. In some cases, a few terms have been selected bythe applicant as necessary and will hereinafter be disclosed in thefollowing description of the present invention. Therefore, it ispreferable that the terms defined by the applicant be understood on thebasis of their meanings in the present invention.

The 3D image display method includes a stereoscopic imaging scheme inwhich two view points are considered and a multi-view imaging scheme inwhich three or more view points are considered. In contrast, a singleview image scheme shown in the related art may also be referred to as amonoscopic image scheme.

The stereoscopic imaging scheme is designed to use one pair of right andleft view images acquired when a left-side camera and a right-sidecamera spaced apart from each other by a predetermined distance capturethe same target object. The multi-view imaging scheme uses three or moreimages captured by three or more cameras spaced apart by a predetermineddistance or angle. Although the following description disclosesembodiments of the present invention using the stereoscopic imagingscheme as an example, the inventive concept of the present invention mayalso be applied to the multi-view imaging scheme.

A stereoscopic image or multi-view image may be compressed and codedaccording to a variety of methods including a Moving Picture ExpertsGroup (MPEG) scheme, and transmitted to a destination.

For example, a stereoscopic image or a multi-view image may becompressed and coded according to the H.264/Advanced Video Coding (AVC)scheme, and transmitted. In this case, the reception system may decode areceived image in reverse order of the H.264/AVC coding scheme, suchthat it is able to obtain the 3D image.

In addition, one of a left view image and a right view image of astereoscopic image or one of multiple-view images may be assigned to animage of a base layer, and the remaining one may be assigned to an imageof an extended layer. The base layer image may be encoded using the samemethod as the monoscopic imaging method. In association with theextended layer image, only information of the relationship between thebase layer image and the extended layer image may be encoded andtransmitted. As an exemplary compression coding scheme for the baselayer image, a JPEG, an MPEG-2, an MPEG-4, or a H.264/AVC scheme may beused. For convenience of description, the H.264/AVC scheme may beexemplarily used in one embodiment of the present invention. In oneembodiment of the present invention, the compression coding scheme foran image of an upper or higher layer may be set to the H.264/Multi-viewVideo Coding (MVC) scheme.

When the MVC scheme is additionally applied to the AVC scheme or theright/left image sequences are coded using only the AVC scheme so as toimplement the stereoscopic display, one point to be duly considered whenbroadcasting corresponding 3D content data is compatibility with the 2Dbroadcast receiver of the related art. For the related broadcastreceiver incapable of supporting the 3D image display, if one of rightand left view images is encoded and transmitted according to a backwardcompatible method, the 2D broadcast receiver recognizes and outputs onlythe corresponding signal, such that it may be possible for a user toview the corresponding content data through the related device. In thefollowing description, a base layer image of a time point where contentdata is transferred for a legacy broadcast receiver may be referred toas base view video data (or a base video), and an extended layer imagetransferred for displaying a 3D image may be referred to as extendedview video data (or an extended video).

In the case of transferring the base view video data and the extendedview video data as described above, a legacy 2D broadcast receiverreceives the base video data so that it can display a 2D image, and a 3Dbroadcast receiver receives base view video data and extended view videodata so that it can display a 3D image. However, unexpected problems mayoccur in a method for displaying subtitle data.

A Digital Video Broadcasting (DVB) system will hereinafter be used as anexample of a system for transmitting, receiving, and processing subtitledata.

The term ‘Subtitle’ in the following description may include not only asubtitle but also displayed image, text data, graphic image, logo, etcwhich are additionally displayed to basic video data.

The DVB broadcast system transmits subtitle data as a variety ofinformation of a subtitle. At this time, the subtitle data may includenot only subtitle display information including configuration, size,position, etc. needed for displaying a subtitle, but also information ofa display color of a subtitle. The subtitle display information includesdisplay definition information associated with a display windowstructure needed for displaying a subtitle, page compositioninformation, region composition information, object data information,and the like. From the viewpoint of a syntax structure for datatransmission, display definition information may be referred to as adisplay definition segment, page composition information may be referredto as a page composition segment, region composition information may bereferred to as a region composition segment, and object data informationmay be referred to as an object data segment.

A related DVB broadcast signal provides only basic subtitle displayinformation. Accordingly, when a 3D broadcast receiver desires todisplay the basic subtitle display information, the basic subtitledisplay information may be represented by a 2D broadcast signal or maynot be displayed. Therefore, it is necessary to transmit informationcapable of allowing even the subtitle display information to bedisplayed in a 3D format, and a broadcast receiver capable of displayingsubtitle data in a 3D format using the above-mentioned information and adata processing method thereof are needed.

In the case of displaying a stereoscopic image, left view video data andright view video data are horizontally shifted by a predetermineddistance so as to implement a 3D effect, and then displayed. At thistime, a variety of representation values (such as a shifted distance)capable of indicating the 3D effect may be used. In accordance with theembodiment of the present invention, a disparity value will hereinafterbe used as such a representation value of the 3D effect.

The 3D effect may be acquired from the process in visual perceptionleading to the sensation of depth from two slightly differentprojections of the world onto the retinas of the eyes. The difference inthe two retinal images may be called horizontal disparity, retinaldisparity, or binocular disparity. Hereinafter, for convenience ofdescription and better understanding of the present invention, thedifference between the two retinal images will only be referred to as‘disparity’.

For example, in the case of transmitting 3D video data, respectivescenes of the 3D video data may have different 3D effects. In this case,disparity values for corresponding scenes are transmitted to a broadcastreceiver, so that the broadcast receiver controls and displays the 3Deffect using the disparity values. Although other representation values(for example, a depth value, a pixel interval, a screen size, etc.)instead of the above disparity values may be used to display the 3Deffect, it should be noted that the embodiments of the present inventionwill exemplarily use the disparity value for convenience of descriptionand better understanding of the present invention.

In the case of transmitting subtitle data using the related DVBtransmission scheme, the 3D broadcast receiver receives base view videodata and extended view video data and displays the received base viewvideo data and the received extended view video data as 3D video data.However, the subtitle data has no information for a 3D display, suchthat it has a disadvantage in that it must display 3D video data as a 2Dformat. In this case, the subtitle can be displayed only as base viewvideo data or an extended view video data, and a user views the subtitlein a 2D format in a different way from a 3D image, so that the user mayexperience dizziness and feel fatigue of eyes.

Accordingly, it is necessary to transmit both 3D video data andinformation of a 3D effect to the related subtitle data. In this way,the 3D effect information may be inserted into the related subtitledisplay information or it is possible to transmit additional subtitledisplay information.

In accordance with a method for transmitting additional subtitle data,the stereoscopic image requires two viewpoint video data (i.e., leftview video data and right view video data) to display the 3D effect, sothat related subtitle display information may be used as subtitledisplay information of one viewpoint, and subtitle display informationof another viewpoint may be additionally transmitted. For example, therelated subtitle display information may be set to a subtitle fordisplaying data at a base view, and subtitle display information of asubtitle to be displayed at an extended view may be additionallytransmitted. In accordance with the above-mentioned method, when twosubtitle display information is transmitted and at the same time 3Deffect information is inserted into one or two subtitle displayinformation and the inserted result is transmitted, a 3D receiver candisplay subtitle data having the 3D effect in the same manner as in amethod for displaying stereoscopic video data.

A method for transmitting the additional subtitle display informationmay be advantageous to a method in which related subtitle displayinformation is modified and transmitted. In other words, the related 2Dbroadcast receiver is designed to process and display only relatedsubtitle display information without processing additional subtitledisplay information undefined in the related subtitle displayinformation, such that the above method for transmitting additionalsubtitle display information can be easily compatible with the related2D receiver.

Therefore, the following embodiment of the present invention willdisclose a method for transmitting subtitle data by constructing notonly related subtitle display information but also other subtitledisplay information for a 3D display. The above-mentioned additionalsubtitle display information may also be referred to as extendedsubtitle display information.

FIG. 1 shows a syntax structure of an extended Display DefinitionSegment (DDS) acting as extended subtitle display information accordingto one embodiment of the present invention.

The DDS includes display width information and display heightinformation of a TV image in which a DVB subtitle is rendered. In otherwords, the DDS indicates a display size of a video image including asubtitle stream to be displayed. In one embodiment of the presentinvention, an extended DDS (DDS_EXT) shown in FIG. 1 is transmitted, sothat a receiver can control an output of a subtitle at an extended view.

Individual fields of the extended DDS shown in FIG. 1 are as follows.

A ‘dds_version_number’ field may indicate aversion of the extended DDS.

A ‘display_window_flag’ field may indicate whether a subtitle displayset associated with the extended DDS is intended to be rendered in awindow within the display size defined by ‘display_width’ and‘display_height’ fields or to be rendered directly within the displaysize defined by ‘display_width’ and ‘display_height’ fields.

A ‘display_width’ field may indicate a maximum horizontal width inpixels of a display assumed by a subtitling stream associated with theextended DDS.

A ‘display_height’ field may indicate a maximum vertical height in linesof a display in lines of a display assumed by a subtitling streamassociated with the extended DDS.

A ‘display_window_horizontal_position_minimum’ field may indicate aleft-hand most pixel of a subtitle display set with reference to aleft-hand most pixel of a display.

A ‘display_window_horizontal_position_maximum’ field may indicate aright-hand most pixel of a subtitle display set with reference to aleft-hand most pixel of a display.

A ‘display_window_vertical_position_minimum’ field may indicate an uppermost line of a subtitle display set with reference to a top line of adisplay.

A ‘display_window_vertical_position_maximum’ field may indicate a bottomline of a subtitle display set with reference to a top line of adisplay.

The above-mentioned fields may be pre-contained in the DDS, and then betransmitted. In this case, information of the same or duplicated fieldshaving been transmitted in the DDS is omitted and as such only thefollowing information may be transmitted.

A ‘page_id’ field 1020 may indicate an identifier (ID) of a page onwhich a subtitle is displayed. In case of a ‘page_id’ value, thesubtitle will be displayed on the same page at a base view and anextended view, so that the ‘page_id’ value may be identical to a‘page_id’ value of a DDS corresponding to the base view, and then betransmitted.

A ‘segment_type’ field 1010 may have a value different from a relatedDDS value (e.g., 0x14), and must have a specific value (e.g., 0x44)capable of identifying an extended DDS.

A ‘target_view_position’ field 1030 may indicate a view position towhich the extended DDS is applied. In other words, the‘target_view_position’ field 1030 indicates viewpoint information fordisplaying a stereoscopic subtitle. For example, if the subtitle displayof a corresponding extended DDS is applied to a left image, the‘target_view_position’ field 1030 may be set to a value of ‘0’. If thesubtitle display of a corresponding extended DDS is applied to a rightimage, the ‘target_view_position’ field 1030 may be set to a value of‘1’.

A ‘minimum_disparity_value’ field 1040 may indicate a minimum value of adisparity capable of being represented by a left image and a rightimage. The lower the disparity value of the ‘minimum_disparity_value’field 1040 (i.e., the closer the disparity value of the‘minimum_disparity_value’ field 1040 is to a negative value), the imageforming position gradually moves to the front of the screen.

A ‘maximum_disparity_value’ field 1050 may indicate a maximum value of adisparity value capable of being represented by a left image and a rightimage. The higher the disparity value of the ‘maximum_disparity_value’field 1050 (i.e., the closer the disparity value of the‘maximum_disparity_value’ field 1050 is to a positive value), the imageforming position gradually moves to the interior of the screen.

The extended DDS may define the range of a disparity value capable ofbeing allocated when a subtitle is displayed through the‘minimum_disparity_value’ field 1040 and the ‘maximum_disparity_value’field 1050.

As described above, in association with the DDS, the extended DDSincludes not only viewpoint allocation information for individualsubtitles, but also 3D effect information (i.e., disparity values), suchthat a receiver can display a subtitle having the 3D effect.

FIG. 2 shows a syntax structure of an extended Page Composition Segment(PCS) acting as extended subtitle display information according to oneembodiment of the present invention.

Referring to FIG. 2, the PCS includes information of constituentcomponents of a displayed subtitle. The PCS may include usage- andpositioning-information of at least one region constructing thedisplayed page. In accordance with one embodiment of the presentinvention, the extended PCS (PCS_EXT) shown in FIG. 2 is transmitted,such that the receiver can control an output of a subtitle at anextended view.

Individual fields of the extended PCS shown in FIG. 2 are as follows.

A ‘page_id’ field may indicate an identifier (ID) of a page on which asubtitle is displayed. In case of a ‘page_id’ value, the subtitle willbe displayed on the same page at a base view and an extended view, sothat the ‘page_id’ value may be identical to a ‘page_id’ value of a DDScorresponding to the base view, and then be transmitted.

A ‘page_time_out’ field may indicate a period, expressed in seconds,after which a page instance is no longer valid and consequently shall beerased from the screen, should it not have been redefined before that.

A ‘page_version_number’ field may indicate a version of the extendedPCS.

A ‘page_state’ field may indicate a status of a subtitling page instancedescribed in the extended PCS.

A ‘region_id’ field may indicate a unique identification of a regionwithin a page. The ‘region_id’ field may display a subtitle in the sameregion at the base view and the extended view, such that it is identicalto a ‘region_id’ value of a PCS corresponding to the base view and thentransmitted.

A ‘region_horizontal_address’ field indicates a horizontal address of atop left pixel of this region. The left-most pixel of the active pixelshas a horizontal address of zero, and the pixel address increases fromleft to right.

A ‘region_vertical_address’ field may indicate a vertical address of atop line of this region. The top line of the frame is a line of zero,and the line address increases by one within the frame from top tobottom.

A ‘target_view_position’ field 2010 may indicate a view position atwhich the extended PCS is applied. That is, the ‘target_view_position’field 2010 may indicate viewpoint information for displaying astereoscopic subtitle. For example, if a subtitle display of acorresponding extended PCS is applied to a left image, the‘target_view_position’ field 2010 may be set to a value of ‘0’. If asubtitle display of a corresponding extended PCS is applied to a rightimage, the ‘target_view_position’ field 2010 may be set to a value of‘1’.

A ‘region_disparity_value’ field 2020 may indicate a disparity between afirst region applied to the left image and a second region applied tothe right image. The ‘region_disparity_value’ field 2020 may indicate ahorizontal displacement of other view on the basis of a target view. Inthe case of transmitting a value of ‘region_disparity_value’ field 2020,a ‘region_horizontal_address’ field and a ‘region_vertical_address’field may be redundant, so that the redundant fields may be omitted asnecessary.

For example, it is assumed that the ‘target_view_position’ field of theextended PCS has a value of 1, the ‘region_disparity_value’ field has avalue of 20, and the ‘region_horizontal_address’ field has a value of N.In this case, a subtitle for the extended PCS is displayed as a rightimage, and a subtitle for the PCS is displayed as a left image. In thiscase, the horizontal position of the subtitle displayed on the leftimage is ‘N’, the horizontal position of the subtitle displayed on theright image is ‘N-20’, so that a binocular parallax is generated inresponse to a difference in horizontal positions between the left imageand the right image, resulting in the occurrence of a 3D effect.

FIG. 3 shows a syntax structure of an extended Region CompositionSegment (RCS) acting as extended subtitle display information.

The RCS includes a list of displayed objects and position information ofthe objects. In accordance with one embodiment of the present invention,the extended RCS (RCS_EXT) shown in FIG. 3 is transmitted, so that thereceiver can control an output of a subtitle at the extended view.

Individual fields of the extended RCS shown in FIG. 3 are as follows.

A ‘region_id field’ may identify a region for which information iscontained in this RCS_EXT.

A ‘region_version_number’ field may indicate a version of this region.

If a ‘region_fill_flag’ field is set to a value of ‘1’, the‘region_fill_flag’ field means signals indicating that the region is tobe filled with the background color defined in the‘region_n-bit_pixel_code’ fields in this segment.

A ‘region_width’ field may specify a horizontal length of this region,and is expressed in number of pixels.

A ‘region_height’ field may specify a vertical length of the region, andis expressed in number of pixels.

A ‘region_level_of_compatibility’ field may indicate a minimum type ofColor Look Up Table (CLUT) that is necessary in the decoder to decodethis region.

A ‘region_depth’ field may identify an intended pixel depth for thisregion.

A ‘CLUT_id’ field may identify a family of CLUTs applied to this region.

A ‘region_n(8,4 and 2)-bit_pixel_code’ field may specify the entry ofthe applied n-bit CLUT as background color for the region when the‘region_fill_flag’ field is set.

A ‘processed_length’ field is the number of bytes from the field(s)within a while-loop that has been processed by the decoder.

An ‘object_id’ field may identify an object shown in the region.

An ‘object_type’ field may identify a type of object.

An ‘object_provider_flag’ field may indicate how this object isprovided.

An ‘object_horizontal_position’ field may specify a horizontal positionof the top left pixel of this object, and is expressed in number ofhorizontal pixels, relative to a left hand edge of the associatedregion.

An ‘object_vertical_position’ field may specify a vertical position ofthe top left pixel of this object, and is expressed in number of lines,relative to the top of the associated region.

A ‘foreground_pixel_code’ field may specify the entry in the appliedCLUT that has been selected as the foreground color of the character(s).

A ‘background_pixel_code’ field may specify the entry in the appliedCLUT that has been selected as the background color of the character(s).

A ‘target_view_position’ field 3010 may indicate a view position atwhich the extended RCS is applied. That is, the target_view_position’field 3010 may indicate viewpoint information for displaying astereoscopic subtitle. For example, if the subtitle display of acorresponding extended RCS is applied to a left image, the‘target_view_position’ field 3010 may be set to a value of ‘0’. If asubtitle display of a corresponding extended RCS is applied to a rightimage, the ‘target_view_position’ field 3010 may be set to a value of‘1’.

An ‘object_disparity_value’ field 3020 may indicate a disparity betweena first object applied to a left image and a second object applied to aright image. A value of the ‘object_disparity_value’ field 3020 mayindicate a horizontal displacement of other view on the basis of atarget view.

FIG. 4 shows a syntax structure of an extended Object Data Segment (ODS)acting as extended subtitle display information according to oneembodiment of the present invention.

The ODS may include data of a plurality of displayed objects. In oneembodiment of the present invention, an extended ODS (ODS_EXT) shown inFIG. 4 is transmitted, so that a receiver can control an output of asubtitle at an extended view.

In case of the ODS, if a disparity field is added in units of eachobject contained in the region of the extended RCS, a disparity can beadjusted in units of each object using the disparity field, so thatdifferent 3D effects can be assigned to each objects contained in theregion. Therefore, the ODS for a base view can be applied even to aprocess for displaying a subtitle at an extended view without anychange. At this time, an identifier (ID) identical to that of the ODSused in the base view may be established in the extended RCS, and thentransmitted. Alternatively, the broadcast receiver may copy or read areceived ODS, such that it may control a subtitle display for theextended view. However, different objects may be used at respectiveviewpoints. At this time, the extended ODS may transmit data of anadditional object. In the embodiment of the present invention, the ODSused for displaying a subtitle for the extended view may be referred toas an extended ODS. In this case, the term ‘extended ODS’ may includethe above-mentioned examples in the following description.

Individual fields of the extended ODS are as follows.

An ‘object_id’ field may identify within the page an object for whichdata is contained in this ‘ODS_EXT’ field.

An ‘object_version_number’ may indicate a version of this segment data.

An ‘object_coding_method’ may specify a method used for coding theobject.

When a ‘non_modifying_colour_flag’ field is set to a value of 1, this‘non_modifying_colour_flag’ field indicates that the CLUT entry value‘1’ is a non-modifying color.

A ‘top_field_data_block_length’ field may specify the number of bytescontained in the ‘pixel-data_sub-blocks’ field for the top field.

A ‘bottom_field_data_block_length’ field may specify the number of bytescontained in the ‘data_sub-block’ field for the bottom field.

A ‘processed_length’ field may indicate the number of bytes from thefield(s) within a while-loop that has been processed by the decoder.

An ‘8_stuff_bits’ field may indicate eight stuffing bits that shall becoded as ‘0000 0000’.

A ‘number_of_codes’ field may specify the number of character codes inthe string.

A ‘character_code’ field may specify a character through its indexnumber in the character table identified in the ‘subtitle_descriptor’field.

Configuration of subtitle display information for displaying astereoscopic subtitle in accordance with one embodiment of the presentinvention and a method for processing the subtitle display informationwill hereinafter be described.

The configuration and process of a Display Definition Segment (DDS) anda Page Composition Segment (PCS) for displaying a stereoscopic subtitleaccording to one embodiment of the present invention will hereinafter bedescribed.

In order to allow a receiver to display a stereoscopic subtitle, thereceiver must receive subtitle information of two views, i.e., onesubtitle information for a base view and the other subtitle informationfor an extended view. A transmission system can transmit a DDS and a PCSfor the base view and the extended DDS and the extended PCS for theextended view.

In this case, in the case where a value incapable of being recognized bya related 2D broadcast receiver is established in a segment type of eachof the extended DDS and the extended PCS, and is then transmitted, therelated 2D broadcast receiver discards the extended DDS and the extendedPCS, and controls a subtitle display using the DDS and the PCS. The 3Dbroadcast receiver controls a subtitle display for the base view usingthe DDS and the PCS, and controls a subtitle display for the extendedview using the extended DDS and the extended PCS, so that it can displaya subtitle having the 3D effect.

Next, the configuration and process of a Region Composition Segment(RCS) for displaying a stereoscopic display according to anotherembodiment of the present invention will hereinafter be described.

The RCS may include information about a list of displayed objects andinformation about positions of the objects in the region. In the case oftransmitting the extended PCS, a segment type value incapable of beinganalyzed by the related 2D broadcast receiver may be established in theextended RCS corresponding to a region identifier (ID) contained in theextended PCS so as to prevent operations of the related 2D broadcastreceiver from being affected, and the established segment type value isthen transmitted. In the case of transmitting the extended RCS inaccordance with one embodiment of the present invention, the segmenttype value may be set to ‘0x41’. In this case, the extended RCS may havethe same structure as in the related RCS. In this embodiment of thepresent invention, the extended RCS may correspond to a structureacquired when the ‘target_view_position’ field 3010 and the‘object_disparity_value’ field 3020 are deleted from the table structureshown in FIG. 3.

In addition, region composition information for the extended view may betransmitted using the RCS (i.e., segment type=0x11) instead of using theextended RCS. In this case, the region ID of this RCS is unavailable inthe received PCS, so that the related 2D broadcast receiver can discardthe above RCS.

The configuration and process of an Object Data Segment (ODS) fordisplaying a stereoscopic subtitle according to another embodiment ofthe present invention will hereinafter be described in detail.

The RCS or the extended RCS includes object information for constructingthe region, and detailed information of a corresponding object may becontained in the ODS and then be transmitted. In this case, in order toprevent operations of the related 2D broadcast receiver from beingaffected, the extended ODS for describing a subtitle object for theextended view may be transmitted. The extended ODS has the samestructure as in the related ODS, and may be assigned another segmenttype value (e.g., 0x43) different from that of the related ODS and thenbe transmitted.

In addition, object information for the extended view may be transmittedusing the related ODS instead of using the extended ODS. In this case,the object ID of the received ODS is unavailable, so that the related 2Dbroadcast receiver can discard the above ODS.

In accordance with one embodiment of the present invention, a variety ofcombinations may be constructed according to configurations of theabove-mentioned ‘DDS_EXT’, ‘PCS_EXT’ ‘RCS_EXT’ (or ‘RCS’), and ‘ODS_EXT’(or ‘ODS’) and methods for transmitting these segments. That is, the‘DDS_EXT’, ‘PCS_EXT’, ‘RCS_EXT’, and ‘ODS_EXT’ are not constructed tohave the same 3D effect, and are constructed to have different 3Deffects. For example, different disparity values may be assigned to the‘DDS_EXT’, ‘PCS_EXT’, ‘RCS_EXT’, and ‘ODS_EXT’. As a result, a varietyof 3D subtitle combinations which have different 3D effects according topages, regions, and objects of individual subtitles can be displayed.

FIG. 5 is a flowchart illustrating a method for receiving and processing3D subtitle data according to one embodiment of the present invention.

Referring to FIG. 5, the broadcast receiver receives a DVB broadcaststream, and extracts subtitle data from the received broadcast stream atstep S5010. In more detail, the broadcast receiver parses a Program MapTable (PMT) from the DVB broadcast stream, obtains a PID value of astream having a stream type (stream_type=0x06), and receives a PacketElementary Stream (PES) corresponding to a DVB subtitle. In this case,the broadcast receiver can obtain basic information of a subtitle fromthe PMT. In accordance with one embodiment of the present invention, thebroadcast receiver determines whether current data is a 3D subtitle byreferring to a ‘subtitling type’ field of a ‘subtitling_descriptor’field contained in the PMT, so that it can inform a user of informationabout the availability or non-availability of a 3D subtitle. Thebroadcast receiver reads a PES packet, which has a value ‘0x20’ of a‘data_identifier’ field and a value ‘0x00’ of a ‘subtitle_stream_id’value, so that it can extract subtitle data using the read PES packet.

The broadcast receiver performs section-filtering of the extractedsubtitle data at step S5020. The broadcast receiver performs filteringof detailed information contained in subtitle data, and outputs thefiltered information to a corresponding buffer. In this case, thesubtitle data may be classified as follows according to values of the‘segment type’ field.

0x10 Page Composition Segment (PCS) for Base View

0x11 Region Composition Segment (RCS) for Base View

0x12 CLUT definition segment for both Base View and Extended View

0x13 Object Data Segment (ODS) for Base View

0x14 Display Definition Segment (DDS) for Base View

0x40 extended Page Composition Segment (PCS_EXT) for Extended View

0x41 extended Region Composition Segment (RCS_EXT) for Extended View

0x43 extended Object Data Segment (ODS_EXT) for Extended View

0x44 extended Display Definition Segment (DDS_EXT) for Extended View

The broadcast receiver decodes subtitle display information for a baseview from the classified DDS, PCS, RCS, and ODS at step S5030. Thebroadcast receiver decodes the DDS, the PCS, the RCS, and the DDS, sothat it can obtain size information of a subtitle to be displayed,position information of the subtitle, object configuration information,object's unique information, and the like. Information needed for thebroadcast receiver to display a subtitle at a base view may also becalled subtitle control information.

The broadcast receiver decodes the ODS, and parses a Color Look Up Table(CLUT), so that it determines subtitle display color information at abase view at step S5040. The broadcast receiver decodes‘pixel-data_sub-block’ data contained in the ODS, so that it can acquirea pseudo-color value of a subtitle to be displayed on a base viewgraphic plane. The broadcast receiver parses the CLUT, so that it canconvert the pseudo-color value into information of a color to beactually displayed.

The broadcast receiver decodes extended subtitle display information forthe extended view from the extended DDS, the extended PCS, the extendedRCS (or RCS), and the extended ODS (or ODS) at step S5050. The broadcastreceiver decodes the extended DDS, the extended PCS, the extended RCS,and the extended ODS (or ODS), so that it can recognize size informationof a subtitle to be displayed, position information of the subtitle,object configuration information, object's unique information, and thelike. Information needed for the broadcast receiver to display asubtitle at the extended view may also be referred to as extendedsubtitle control information as necessary.

The broadcast receiver decodes the extended ODS (or an ODS), and parsesa CLUT, so that it determines subtitle display color information at aextended view at step S5060. The broadcast receiver decodes‘pixel-data_sub-block’ data contained in the extended ODS (or an ODS),so that it can acquire a pseudo-color value of a subtitle to bedisplayed on the extended view graphic plane. The broadcast receiverparses the CLUT, so that it can convert the pseudo-color value intoinformation of a color to be actually displayed.

In a 3D display, a color of a left view subtitle may be equal to a colorof a right view subtitle. In this case, the broadcast receiver maydetermine only once the color information of a subtitle to be displayed,and may use subtitle color information of other viewpoint by reading thedetermined color information. In this case, step S5060 may herein beomitted or a process for copying or reading the color information thathas been determined at step S5040 may be carried out.

The broadcast receiver controls a subtitle for the base view and asubtitle for the extended view according to individual subtitle controlinformation, and outputs the controlled subtitles at step S5070. Thebroadcast receiver outputs the base view subtitle along with base viewvideo data according to subtitle control information and outputs theextended view subtitle along with extended view video data according toextended subtitle control information, so that it can display a 3Dsubtitle.

In the above-mentioned steps, the step for processing subtitle displayinformation for a base view subtitle and the other step for processingextended subtitle display information of an extended view subtitle neednot always be carried out in the above order. If necessary, subtitledisplay information for the extended view may be first carried out, orsubtitle display information for the base view and subtitle displayinformation for the extended view may be simultaneously carried out.

FIG. 6 is a block diagram illustrating a broadcast receiver forreceiving and processing 3D subtitle data according to one embodiment ofthe present invention.

Referring to FIG. 6, the broadcast receiver includes a demultiplexer(denoted by ‘MPEG2 TS Demux (PID filter)’) 6010, a section filter 6020,an Extended View (EV) subtitle decoder 6030, a Base View (BV) subtitledecoder 6040, a composition buffer 6050, a CLUT processor (denoted by‘CLUT’) 6060, an EV pixel buffer 6070, a BV pixel buffer 6080, and a 3Dgraphics controller 6090.

Constituent components of the broadcast receiver shown in FIG. 6 willhereinafter be described in detail. In more detail, the broadcastreceiver shown in FIG. 6 is designed to receive and process the 3Dsubtitle data shown in FIG. 5. The same or duplicated parts as those ofFIG. 5 will be briefly described.

In the broadcast receiver, a receiving unit (not shown) receives aMoving Picture Expert Group 2 Transport Stream (MPEG2 TS) includingsubtitle data, and the demultiplexer 6010 performs filtering of thereceived MPEG2 TS using a PID corresponding to subtitle data so that itextracts and outputs subtitle data.

The section filter 6020 performs section-filtering of subtitle data, sothat it outputs PCS, PCS_EXT, RCS, RCS_EXT, DDS, DDS_EXT, ODS, ODS_EXT,and Color Look Up Table Definition Segment (CLUTDS) data.

In the following description, the demultiplexer 600 for extractingsubtitle data from the received broadcast signal and the section filter6020 for extracting and outputting display information and CLUTDS of asubtitle may be contained in one extraction unit as necessary.

In this case, PCS, RCS, DDS, ODS, PCS_EXT, RCS_EXT, DDS_EXT, and ODS_EXTmay be buffered in the composition buffer 6050, and the buffered resultsmay be applied to the 3D graphics controller 6090. In addition, PCS,RCS, DDS, and ODS may be applied to the BV subtitle decoder 6040, andPCS_EXT, RCS_EXT, DDS_EXT, and ODS_EXT may be applied to the EV subtitledecoder 6030.

The CLUT processor 6060 processes the CLUTDS, so that it outputs displaycolor information to the BV pixel buffer 6080 and the EV pixel buffer6070.

The BV subtitle decoder 6040 decodes PCS, RCS, DDS, and ODS, so that itdecodes subtitle data for the base view and subtitle display informationfor the base view and outputs the decoded subtitle data and the decodedsubtitle display information to the BV pixel buffer 6080. The EVsubtitle decoder 6030 decodes PCS_EXT, RCS_EXT, DDS_EXT, and ODS_EXT, sothat it decodes subtitle data for the extended view and subtitle displayinformation for the extended view and outputs the decoded subtitle dataand the decoded subtitle display information to the EV pixel buffer6070.

The 3D graphic controller 6090 receives PCS, RCS, DDS, ODS, PCS_EXT,RCS_EXT, DDS_EXT, and ODS_EXT from the composition buffer 6050, andreceives subtitle display information for the base view, ODS and colorinformation for the base view from the BV pixel buffer 6080. The 3Dgraphics controller 6090 receives subtitle display information for theextended view, ODS_EXT and color information for the extended view fromthe EV pixel buffer 6070. The 3D graphics controller 6090 reads thereceived information, so that it controls subtitles of respectiveviewpoints and outputs the controlled subtitles.

In accordance with another embodiment of the present invention, the BVsubtitle decoder 6040 decodes the ODS and the EV subtitle decoder 6030decode the ODS_EXT, so that the BV subtitle decoder 6040 and the EVsubtitle decoder 6030 acquire information of a displayed subtitleobject. The 3D graphics controller 6090 receives coordinates-, size-,and configuration-information (for example, PCS, RCS, DDS, PCS_EXT,RCS_EXT, and DDS_EXT) of a displayed subtitle object, so that it maycontrol the 3D subtitle display using the received information.

The method disclosed in the present invention may be implemented in theform of program commands executable by a variety of computer means, andrecorded on a computer-readable recording medium. The computer-readablerecording medium may include program commands, data files, datastructures, etc. individually or in combination. The program commandsrecorded on the medium may be ones specially designed and configured forthe present invention or ones known and available to those skilled incomputer software. Examples of the computer-readable recording mediuminclude magnetic media such as a hard disk, a floppy disk and a magnetictape, optical media such as a compact disc read only memory (CD-ROM) anda digital versatile disc (DVD), magneto-optical media such as afloptical disk, and hardware devices specially configured to store andexecute program commands, such as a ROM, a random access memory (RAM)and a flash memory. Examples of the program commands include high-levellanguage codes that may be executed by a computer using an interpreter,etc., as well as machine language codes such as those produced by acompiler. The above-stated hardware devices may be configured to operateas one or more software modules to perform the operation of the presentinvention, and vice versa.

Although the present invention has been described in conjunction withthe limited embodiments and drawings, the present invention is notlimited thereto. Those skilled in the art will appreciate that variousmodifications, additions and substitutions are possible from thisdescription. Therefore, the scope of the present invention should not belimited to the description of the exemplary embodiments and should bedetermined by the appended claims and their equivalents.

MODE FOR THE INVENTION

Various embodiments have been described in the best mode for carryingout the invention.

INDUSTRIAL APPLICABILITY

As apparent from the above description, embodiments of the presentinvention may be wholly or partially applied to a digital broadcastingsystem.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

The invention claimed is:
 1. A method of processing a digital broadcastsignal for a 3-dimensional, 3D, content, the method comprising: encodingvideo data for the 3D content into a stream, the video data comprising aleft picture for a left view and a right picture for a right view for a3D image; generating signaling information for the video data, thesignaling information including a Program Map table (PMT) providing amapping between a program number and program elements of a programincluding the 3D content, wherein the PMT includes subtitling descriptorincluding subtitling type information, and wherein the subtitling typeinformation indicates an existence of a 3D subtitle for the 3D content;generating packet data for subtitling of the 3D content, the packet dataincluding subtitle segment, wherein the subtitle segment includesdisparity information indicating a difference between horizontalpositions of subtitles representing a same point in space in the rightand left view of the 3D image for a page; and transmitting the broadcastsignal including the video data, the packet data, and the signalinginformation; wherein the subtitle segment further includes regioninformation identifying at least one region within the page, and regiondisparity information indicating differences between horizontalpositions of subtitles in the at least one region identified by theregion information; wherein the subtitle segment further includes regionsize information specifying a horizontal width of the at least oneregion which is expressed in pixels.
 2. The method of claim 1, whereinthe subtitle segment further includes object information identifying atleast one object within the at least one region, and the disparityinformation indicates differences between horizontal positions ofsubtitles for the at least one object identified by the objectinformation.
 3. The method of claim 1, wherein the broadcast signalfurther includes range information indicating depth range of the 3Dimage.
 4. The method of claim 3, wherein the range information includesmaximum disparity information indicating intended largest disparity ofthe 3D image and minimum disparity information indicating intendedsmallest disparity of the 3D image.
 5. An apparatus for receiving adigital broadcast signal for a 3-dimensional, 3D, content, the methodcomprising: a receiving unit configured to receive a broadcast signalincluding video data for the 3D content, wherein the video data comprisea left picture for a left view and a right picture for a right view fora 3D image; signaling information for the video data, the signalinginformation including a Program Map table (PMT) and to extract packetdata for subtitling of the 3D content from the received broadcastsignal, wherein the PMT includes subtitling descriptor includingsubtitling type information, wherein the subtitling type informationindicates an existence of a 3D subtitle for the 3D content, wherein thepacket data includes a subtitle segment, and wherein the subtitlesegment includes disparity information indicating a difference betweenhorizontal positions of subtitles representing a same point in space inthe right and left view of the 3D image for a page; a controllerconfigured to control a display of subtitle in the 3D image for the 3Dcontent based on the subtitling type information and the subtitlesegment; wherein the subtitle segment further includes regioninformation identifying at least one region within the page, and regiondisparity information indicating differences between horizontalpositions of subtitles in the at least one region identified by theregion information; wherein the subtitle segment further includes regionsize information specifying a horizontal width of the at least oneregion which is expressed in pixels; wherein the subtitle segmentfurther includes region size information specifying a horizontal widthof the at least one region which is expressed in pixels.
 6. Theapparatus of claim 5, wherein the subtitle segment further includesobject information identifying at least one object within the at leastone region, and the disparity information indicates differences betweenhorizontal positions of subtitles for the at least one object identifiedby the object information.
 7. The apparatus of claim 5, wherein thebroadcast signal further includes range information indicating depthrange of the 3D image.
 8. The method of claim 7, wherein the rangeinformation includes maximum disparity information indicating intendedlargest disparity of the 3D image and minimum disparity informationindicating intended smallest disparity of the 3D image.